bantu dong kak pakai cara ok

Nmr 18
f(x) = y = 2x+2
uji titik, masukkan x=0
y = 2(0)+2
y = 2
(0,2)
Lihat optionnya, hanya B yg grafiknya melalui (0,2).
♦ B ♦

Nmr 19
(-1,7) & (0,2)
Pers. garisnya :
y-7/2-7 = x+1/0+1
y-7 = -5x-5
5x+y = 2
gradiennya (m) = -a/b = -5/1 = -5.
Tegak lurus dgn garis yg gradienya :
m1.m = -1
m1.(-5) = -1
m1 = -1/-5
m1 = 1/5
a. 5x-y = -23 → m1 = -5/-1 = 5
b. x-5y = 37 → m1 = -1/-5 = 1/5 ♣BENAR♣
c. x+5y = -37 → m1 = -1/5
d. 5x+y = 11 → m1 = -5/1 = -5

Nmr 20
(3,1) & (-4,-13)
Pers. garisnya :
y-1/-13-1 = x-3/-4-3
y-1/-14 = x-3/-7
y-1 = 2x-6
2x-y = 5
titik A(10,p) terletak pada garis
2(10)-y = 5
20-y = 5
y = 15
Maka, nilai p = 15
♠B♠